Pickle the onions: In a bowl, toss together 1/2 red onion (thinly sliced), 2 Tbsp. red wine vinegar, 1 tsp. ground sumac, and 1/4 tsp. kosher salt. Allow it to sit for about 15-20 minutes, tossing occasionally to ensure the onions are evenly coated.
Marinate the chicken: In a separate bowl, combine 1.5 lbs. boneless, skinless chicken thighs with 2 Tbsp. fresh lemon juice, 1 1/2 tsp. ground turmeric, 1 tsp. ground coriander, 3/4 tsp. kosher salt, and 1/2 tsp. black pepper. Mix well and let it marinate for 15-20 minutes.
Preheat the oven: Set your oven to 375ºF (190ºC). This ensures your chicken cooks evenly once placed in the oven.
Brown the chicken: In a large oven-safe skillet, heat 2 Tbsp. extra-virgin olive oil over medium heat. Add the marinated chicken and cook for about 5 minutes on each side until golden brown. Remove the chicken from the skillet and set it aside for now.
Sauté the aromatics: In the same skillet, add 1 cup thinly sliced scallions, 3-4 minced garlic cloves, and 2 Tbsp. minced fresh ginger. Sauté for about 3-4 minutes until everything is fragrant.
Toast the rice: Stir in 1 1/2 cups short-grain white rice into the skillet and toast for about 1 minute, stirring frequently to prevent burning.
Add the liquids: Pour in 1 3/4 cups chicken broth and 1 (13.5-oz.) can lite coconut milk. Stir well and bring the mixture to a boil.
Combine and bake: Once boiling, place the browned chicken on top of the rice mixture. Cover the skillet with a lid or aluminum foil and bake in the preheated oven for 25 minutes.
Add the finishing touches: After 25 minutes, remove the skillet from the oven. Top with the pickled onions and garnish with fresh cilantro leaves before serving.